Group connection with several conditions, and one of them with a constant

Question

Here is a snippet of my (VB) LINQ:

From event_evn In xmlEvents.Descendants("event_evn") _
Join genre_gnr In xmlGenre.Descendants("genre_gnr") On event_evn.Element("evn_gnr_id") Equals genre_gnr.Element("gnr_id").Value _
Group Join eventdata_eda In xmlEventData.Descendants("eventdata_eda") On _
eventdata_eda.Element("eda_evn_id").Value Equals event_evn.Element("evn_id").Value And _
eventdata_eda.Element("eda_dty_id").Value Equals "15" _
Into edaList = Group _
From eventdata_eda In edaList.DefaultIfEmpty() _
Where _

I get an error message on the last line with this message: "You must reference at least one range variable on both sides of the Equals operator. How to perform a group connection with several conditions, where one of these conditions is compared to a constant?

I found two places with the answer:
http://forums.asp.net/p/1209451/2127071.aspx#2127071
LINQ to SQL - Left Outer Join several join conditions

However, this is in both C # and VB.

Thanks in advance:)

Answer 1

, , LINQ , , :

From event_evn In xmlEvents.Descendants("event_evn") _
Let JoinVals = New With { .EvnId = event_evn.Element("evn_id").Value, _
                          .Fifteen = "15" } _
Join genre_gnr In xmlGenre.Descendants("genre_gnr") On event_evn.Element("evn_gnr_id")     Equals genre_gnr.Element("gnr_id").Value _
Group Join eventdata_eda In xmlEventData.Descendants("eventdata_eda") On _
eventdata_eda.Element("eda_evn_id").Value Equals JoinVals.EvnId And _
eventdata_eda.Element("eda_dty_id").Value Equals JoinVals.Fifteen _
Into edaList = Group _
From eventdata_eda In edaList.DefaultIfEmpty() _
Where _

Answer 2

, :

...
Group Join j In <YourJoinTable> On <YourEqualsClauses> Into Group
From g In Group.Where(Function(f) f.ColumnName = "<constantValue>").DefaultIfEmpty()

LinqPad, SQL.

...
LEFT OUTER JOIN <YourJoinTable> ON <YourEqualsClauses>
AND [<YourJoinTable>].[ColumnName] = '<constantValue>'